求翻译：本方案驱动电机选用无刷直流电子换相来代替机械换相的直流电机，主要研究PWM调速及电子换相的效率和噪音问题是什么意思？

The drive motor of the program selection of Brushless DC electronic commutation instead of a mechanical commutation of the DC motor, pwm speed control and electronic commutation, the efficiency and noise problems

The drive motor with a brushless DC electronic switch that is to replace the mechanical switch of the DC motor, the main research PWM speed and efficiency of the electronic switch, and noise issues

This plan actuation electrical machinery selects not brushes the direct-current electron phase change to replace the mechanical phase change the direct current machine, mainly studies the PWM velocity modulation and the electronic phase change efficiency and the noise question

This programme selection brushless DC electric motor commutation to replace mechanical commutation of DC motor, primary research on PWM electronic commutation speed and efficiency and noise problems

正在翻译，请等待...